p1606 is not an o2 code, it is a code for communication between your ABS module and ECU is not working properly, it has nothing to do with your misfire.. and P0421 is a warm up catalyst code, it as well has nothing to do with your misfire.. id change your coil pack number 2 around with another one, then drive it till the ses light comes back on and see which misfires now.. its either your coil, if the misfire changes cylinders, or its the plug or icm for the number 2 cylinder, and if its the icm it controls that whole bank, so youll just change one icm.. if your plug is bad id go ahead and replace them all.. and i mean.. honestly.. id change them all regardless.. im guessing coil or icm...

 

it only seems to run like **** when it's hot. When it cold and you first start driving it runs great. Is that the o2 sensors being bad. I will start with the plugs with the misfire, change them and switch the coil packs and see if i get another misfire.